Abstract: Objective: To prepare multilayer sodium alginate/chitosan microspheres containing vascular endothelial growth factor (VEGF) and vancomycin (VAN) and discuss their in vitro anti-infective ability and stability. Methods: Multilayer drug-loaded microspheres were prepared by infusion method and layer-by-layer self-assembly technique. The in vitro anti-infective ability of microspheres was tested by paper strip method. The drug loading and encapsulation efficiency of VEGF and VAN in the microspheres were determined by ELISA and UV spectrophotometry. The surface and cross section morphology of microspheres were observed by scanning electron microscope after different temperatures and light treatment of the microspheres. The changes of effective release amount of VEGF and VAN in microspheres after different conditions were determined. Results: The prepared microspheres were spherical in shape. After the microspheres were dissolved, the diameter of the bacteriostatic loop of the solution against Staphylococcus aureus (ATCC25923) was (12.61±1.01)mm. After treatment under different conditions, the microspheres diameter was 900-1100μm, the surface was complete. There was a little fold, and the cross-section was dense network structure. The drug loading of VEGF and VAN in the microspheres were 6.63 × 10^-5% and 1.39%, respectively, and the encapsulation efficiencies were 72.1% and 3.37%, respectively. Under different conditions, the effective release amount of VEGF and VAN in the microspheres decreased. Conclusion: An uniform particle size was prepared, which had certain inhibitory effect on Staphylococcus aureus and required low temperature (-80℃) dark storage.

Key words: Sodium alginate, Chitosan, Vascular endothelial growth factor, Vancomycin, Microspheres